In this article we discuss the applicability of global scattering functions for structure analysis of Grazing Incidence Small Angle X-ray Scattering (GISAXS) data. Contrary to rigorous analysis of the full 2-D detector image, which can be performed with complex simulation models, the global scattering functions described here will be used to model transverse detector scans in the $q_{\parallel}$ reciprocal scattering planes. In contrast to a full GISAXS analysis, this procedure cannot explain structural features perpendicular to the sample plane. The discussed method is useful for the analysis of weakly correlated films. These films are e.g. found in polymer inorganic composite materials based on commercially available nanoparticles. In hybrid material systems polydisperse structures, including particle aggregates without precisely defined shape are formed. The pictured approach, which models scattering in terms of structural levels, has been previously applied with success in conventional transmission SAXS geometry. It is based on conventional exponential and power laws. Hence, data analysis becomes less complex compared to simulation approaches. Here we examine if this unified fitting model can be used to model diffuse, non specular scattering resulting from GISAXS. In this context the applicability and limit of its application to diffuse scattering in the GISAXS geometry is discussed. Furthermore diffuse $q_{\parallel}$ scattering from different ideal particle types is simulated and compared with fitted results. To verify our approach, fit results from experimental GISAXS curves obtained for real samples are compared with results from Scanning Probe Microscopy and Scanning Electron Microscopy studies. The samples investigated range from evaporated Au films to hybrid TiO2/polymer films and demonstrate the usefulness in the structural analysis of complex films.

Carbon nanotubes (CNTs) are being looked at as a promising material for the submicron or nanometre scale electronic and electro-mechanical devices. At this size, the thermal transport properties of the components become extremely important with regard to the proper functioning of the device. As it is difficult to accurately measure these properties in case of nano devices, predictions using modeling and simulation play an important role in the design of these devices. In this paper, we have estimated and analyzed the thermal conductance of one single-walled carbon nanotube (SWNT) depending upon its geometrical features. We have further extended the simulation to predict the thermal conductance of multi-walled carbon nanotubes (MWNTs). It was found that the SWNT depicts high thermal conductance which depends largely on its geometry and chirality and an MWNT shows very high conductance varying with tube diameter, length and number of shells.

A widely tunable injection seeded Ti:sapphire ring cavity has been developed and characterized. The seeding source is a single mode quasi continuous wave Ti:Sa laser, continually tunable over more than 2.5 cm-1 (75 GHz). Its short term (pulse to pulse) stability is on the order of ±3.2 MHz at a repetition rate of 20 Hz. The long term absolute stability is limited up to now to about ±10 MHz. These frequency characteristics are transferred to the pulsed emission with minor degradations. The frequency chirps and shifts during the pulses are also studied using an optical heterodyne technique.

The FT-IR absorption and Raman scattering were used in order to obtain information concerning the short range order in xCuO·(100-x)[ 2TeO2·PbO·0.2Ag2O](0 ≤x≤ 5 mol%) glasses. Moreover, the changes in tellurium atoms coordination that occurs with copper oxide addition were followed. Both techniques reveal that tellurium is disposed in the network structure in trigonal bipyramids (TeO4), trigonal pyramids (TeO3) along with TeO3+1 polyhedra units. Increasing the CuO content in the glasses changes the coordination of tellurium atoms from 4 to 3 through the so-called 3+1 intermediate units, simultaneously with the increase of the non-bridging oxygen (NBOs) ions amount causing a depolymerization process in the glass structure.

Analysis of tunable photonic microwave bandpass filter with negative coefficient based on an electro-optic phase modulator (EOPM) followed by a fiber Michelson interferometer with orthogonally polarized arms is presented. The Michelson interferometer is made by connecting two fibers to the output ports of a polarization beamsplitter (PBS) and attaching high reflecting Bragg gratings at the other end of the fibers. The negative coefficient is generated from the optical interference of the two phase modulated optical carriers when recombined at the PBS. A two-tap microwave bandpass filter with one negative coefficient is presented. The chromatic dispersion is expected to have no effect on this filter. The filter is tunable over a wide frequency bandwidth using short fiber lengths.

The novel red-emitting phosphors (Sr0.75Ba0.25)MoO4:Pr3+, R+ (R = Li, Na, K) were prepared by solid-state reaction. The crystallization and particle sizes of samples have been investigated by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM images show that the grain size of phosphor is well agreement with the theoretical calculation data from the XRD patterns. Corresponding to the 3P0 $\to$ 3F2 transition of Pr3+, the intensely red emission at 647 nm resulted from exciting the powders with blue light. The concentrations of doping ions, replace the different parts of substrate and the charge compensator R+ (R = Li, Na, K) in the phosphor system can significantly influence the properties of phosphor.

A new model for a tunnel junction with a ferroelectric-ferromagnetic-ferroelectric composite barrier and two magnetic electrodes is evaluated. By reversing the electric polarisation in the ferroelectric layers and the magnetisation in the electrodes independently or simultaneously, sixteen distinct resistive states are obtained successfully. The tunnelling electroresistance ratio, the spin-filtering ratio and the conductance as functions of the barrier thickness, the exchange splitting and the electric polarisation are also investigated in detail. Compared with conventional tunnel junctions, our theoretical model presents more resistive states that potentially may lead to a tremendous increase in multivalue logic state storage in next generation memory cells.

We report on the investigation of the electrical and optical properties of hybrid active layers for multicolor and white light-emitting organic devices consisting of a conjugated polymer – polyfluorene (PFO) mixed with inorganic nanoparticles. We have analyzed the behavior of absorption, photoluminescence (PL) spectra as well as electroluminescence (EL) of PFO-based hybrid films after introduction of inorganic nanoparticles having acceptor properties (ZnO, Si) to compare their emission efficiency. We have demonstrated the possibility to tune the PL/EL emission color from green to blue by changing the PFO/ZnO nanoparticles concentration ratio with obtaining the white color at intermediate concentration ratios.

The loss calculation in soft magnetic materials, used in the manufacturing industry, is still ruled by Steinmetz's simple law. It has remained unchallenged for more than a century, unproven but successfully used by designers of magnetic components. Based on experiments carried out on soft NO Fe–Si and Mn–Zn ferrite samples, in this paper we present a model of Steinmetz's approximation, based on the hyperbolic model. We also make suggestions for the formula's possible extension to a wider range of coercivity, possibly covering not only soft iron but also other groups of magnetic materials as well, used in industry.

The encapsulation of the active layers (organic semiconductors, electrodes, transparent conductive oxides, etc.) of organic electronic devices developed onto flexible polymeric substrates is one of the most challenging issues in the rapidly emerging area of organic electronics. The importance for the protection of the active layers arises from the fact that these are very sensitive when they are subjected to the atmosphere, since the permeation of the atmosphere's water vapour (H2O) and oxygen (O $_{2})$ gases induces corrosion effects, film delamination and finally, failure of the organic electronic device. In addition, the encapsulation layers contribute to the long-term stability of the whole device enabling its use in outdoor environments (e.g. in the case of flexible photovoltaic cells-OPVs). A promising approach for the encapsulation of flexible organic electronics includes the development of multilayers that consist of hybrid polymer materials and inorganic layers onto flexible polymeric substrates, such as poly(ethylene terephthalate) (PET). This approach leads to a significant improvement of the barrier performance of the whole structure, due to the synergetic effect of the confinement of the permeation to the defect zones of the inorganic layer, and the formation of chemical bonds between the hybrid polymer and the inorganic layer. The knowledge of their optical properties and their correlation with their barrier performance are of major importance since it will contribute towards the optimization of their functionality. In this work, we provide an overview on the results concerning the use of hybrid polymers as ultra high barrier materials and moreover we discuss on the effect of inclusion of SiO2 nano-particles on their optical properties and barrier performance.

Solid state nuclear track detectors (SSNTDs), such as CR-39, have been used to detect energetic charged particles and neutrons. Of the neutron and charged particle interactions that can occur in CR-39, the one that is the most easily identifiable is the carbon breakup reaction. The observation of a triple track, which appears as three alpha particle tracks breaking away from a center point, is diagnostic of the 12C(n, n’)3α carbon breakup reaction. Such triple tracks have been observed in CR-39 detectors that have been used in Pd/D co-deposition experiments. In this communication, triple tracks in CR-39 detectors observed in Pd/D co-deposition experiments are compared with those generated upon exposure to a DT neutron source. It was found that both sets of tracks were indistinguishable. Both symmetric and asymmetric tracks were observed. Using linear energy transfer (LET) curves and track modeling, the energy of the neutron that created the triple track can be estimated.

A new application of multilayer structures containing single-negative material is proposed as spatial filter. The spatial filter has an ultra-compact structure (only two periods) and is based on that the transmittance of waves through the structure is not sensitive to the incident angle. Through optimised structure parameters, the filter permits waves propagating within a wide spatial-frequency bandwidth and with perfect transmittance. The spatial-frequency bandwidth is tunable by adjusting structure parameter and frequency.

The optical gaps of the low-bandgap PPVs (PM-20, PM-19, PM-18) are decreased down to 1.6-1.7 eV compared with that of MDMO-PPV (2.2 eV). The best lateral hole mobility was determined to be 2.1 × 10-3 cm2/V s (PM-18) in field effect transistors and exceeds that of MDMO-PPV (poly-[ 2-methoxy-5-(3'.7'-dimethyloctyloxy)-1.4-phenylenevinylene], 8.5 × 10-4 cm2/V s). This allows to reduce the PCBM ([6.6]-phenyl-C $_{61(71)}$ -butanoic acid methyl ester) content in solar cell devices down to 1:2 w/w giving a better $\eta_{\rm AM1.5}$ than for MDMO-PPV:[60]-PCBM cells (PM-19:[60]-PCBM 2.32% on ITO-PET, 2.86% on ITO glass). The charge transfer to PCBM as acceptor occurs quite normally and shows an effective charge separation using light-induced spin resonance spectroscopy (LESR). The [70]-PCBM $^{-\bullet}$ signals are shifted to lower field related to those of [60]-PCBM $^{-\bullet}$ and overlap more with the polaron signal of PM-19. The LESR g-factor components of [70]-PCBM $^{-\bullet}$ are reported for the first time. The external quantum efficiency peak values achieve up to 42% at ~350–400 nm and 26% at ~640 nm (PM-19:[60]-PCBM).

In this paper we present an investigation into the possible link between the pressure of the gas in the surrounding environment and the rate of ice sublimation in a VPSEM (variable pressure scanning electron microscope). Although this is mainly significant to an electron microscopist working in a variable pressure environment, it is relevant to people working at low pressures who wish to have control over the rate of sample dehydration where the input of water vapour is not a viable alternative.

Dye-coated single microspheres exhibit whispering gallery modes (WGMs) within the spontaneous emission bandwidth of the dye spectrum. These modes are extremely sensitive to the size, shape and the refractive index besides their coating thickness. Aden and Kerker theory has been used to simulate the WGMs. The effect of refractive index of the medium and the microsphere on WGMs has been studied. Variations are observed in the decay rates of the excited state with the size of the microspheres on varying the refractive index of the medium surrounding the microcavity. It is found that (i) the observed quality factors (Q-values) are smaller by several orders of magnitude than those expected theoretically and (ii) the radiative rates are enhanced for Q-values > 3 × 103.

Contact potential difference (CPD) was measured by macroscopic Kelvin probe instrument and scanning Kelvin probe microscope on Al, Ni and Pt on ITO substrates at ambient conditions. CPD values measured by scanning Kelvin probe microscope and macroscopic Kelvin probe are close within the error of about 10–30% for large studied objects, whereas scanning Kelvin probe microscope signal decreases, when the object size becomes smaller than 1.4 μm. CPD and electric field signals measured using many-pass technique allowed us to estimate the influence of electrostatic field disturbance, especially, in the case of small objects.

This paper describes the microstructure of a Roman ferrous nail through its observation by transmission electron microscopy. The morphologies of pearlitic colonies and ferritic grains are detailed and the relationship between pearlitic colonies and ferrite in Roman nails is explicitly demonstrated for the first time. Observations also confirm the presence of dislocations in ferritic grains and attest to the existence of very small carbide precipitates that have not been pointed out previously in standard archaeometric studies.

The growing market for flexible electronics devices is asking for reduction of manufacturing process complexity. One way to reduce complexity is to decrease the number of single components of a device by using integrated modules, i.e. device components providing multiple functions. In this article, the concept of a self-powered electrochromic graphics display device is demonstrated. The device is based on a three electrode system comprising an electrochromic electrode, a battery anode and a battery cathode, all in contact with a common electrolyte. The electrochromic electrode can be charged and discharged directly when connected to either the anode or cathode. Such a self-powered display integrates the functions of both a display and a battery. As part of a flexible electronics device, a self-powered display would be able to power other components, such as driver electronics.

In this paper, we discuss the effect of flexible substrates on the characteristics of two organic optoelectronic devices, namely P3HT:PCBM-based photovoltaic bulk heterojunctions and pentacene-based phototransistors. In addition, we have developed anode materials deposited by ion beam sputtering, a technique which satisfies the low temperature deposition requirements associated with the use of plastic substrates. The anode materials consisted of indium tin oxide (ITO) and ITO/metal/ITO tri-layers. The use of tri-layer anodes in P3HT:PCBM-based solar cells resulted in an increase in the fill factor and the power conversion efficiency reached a value of 2% with an ITO(70 nm)/Ag(14 nm)/ITO(70 nm) anode deposited on a polyphthalate carbonate substrate. In the case of phototransistors, a photosensitivity of 1.6 × 104 under illumination at 365 nm (with a power intensity of 7 mW/cm2) was obtained in the off-state of the transistor. We have fine-tuned the anode structure and deposition/annealing conditions towards flexible organic devices and optimal device characteristics.